This is a turbo tax issue that needs to be fixed. As mentioned by others in this thread TD Ameritrade, Fidelity, and E*TRADE all report these negative values, which seems to be in accordance with the latest 1099-B instructions (linked below). No work-around by TT clients should be required.
https://www.irs.gov/pub/irs-pdf/i1099b.pdf
“Box 1d. Proceeds
Enter the gross cash proceeds from all dispositions (including short sales) of securities, commodities, options, securities futures contracts, or forward contracts. Show a loss, such as one from a closing transaction on a written option or forward contract, as a negative amount by enclosing it in parentheses.”
